<html><!-- Created using the cpp_pretty_printer from the dlib C++ library.  See http://dlib.net for updates. --><head><title>dlib C++ Library - chinese_whispers.h</title></head><body bgcolor='white'><pre>
<font color='#009900'>// Copyright (C) 2012  Davis E. King (davis@dlib.net)
</font><font color='#009900'>// License: Boost Software License   See LICENSE.txt for the full license.
</font><font color='#0000FF'>#ifndef</font> DLIB_CHINESE_WHISPErS_Hh_
<font color='#0000FF'>#define</font> DLIB_CHINESE_WHISPErS_Hh_

<font color='#0000FF'>#include</font> "<a style='text-decoration:none' href='chinese_whispers_abstract.h.html'>chinese_whispers_abstract.h</a>"
<font color='#0000FF'>#include</font> <font color='#5555FF'>&lt;</font>vector<font color='#5555FF'>&gt;</font>
<font color='#0000FF'>#include</font> "<a style='text-decoration:none' href='../rand.h.html'>../rand.h</a>"
<font color='#0000FF'>#include</font> "<a style='text-decoration:none' href='../graph_utils/edge_list_graphs.h.html'>../graph_utils/edge_list_graphs.h</a>"

<font color='#0000FF'>namespace</font> dlib
<b>{</b>

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
    <font color='#0000FF'>inline</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> <b><a name='chinese_whispers'></a>chinese_whispers</b> <font face='Lucida Console'>(</font>
        <font color='#0000FF'>const</font> std::vector<font color='#5555FF'>&lt;</font>ordered_sample_pair<font color='#5555FF'>&gt;</font><font color='#5555FF'>&amp;</font> edges,
        std::vector<font color='#5555FF'>&lt;</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font><font color='#5555FF'>&gt;</font><font color='#5555FF'>&amp;</font> labels,
        <font color='#0000FF'>const</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> num_iterations,
        dlib::rand<font color='#5555FF'>&amp;</font> rnd
    <font face='Lucida Console'>)</font>
    <b>{</b>
        <font color='#009900'>// make sure requires clause is not broken
</font>        <font color='#BB00BB'>DLIB_ASSERT</font><font face='Lucida Console'>(</font><font color='#BB00BB'>is_ordered_by_index</font><font face='Lucida Console'>(</font>edges<font face='Lucida Console'>)</font>,
                    "<font color='#CC0000'>\t unsigned long chinese_whispers()</font>"
                    <font color='#5555FF'>&lt;</font><font color='#5555FF'>&lt;</font> "<font color='#CC0000'>\n\t Invalid inputs were given to this function</font>"
        <font face='Lucida Console'>)</font>;

        labels.<font color='#BB00BB'>clear</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>;
        <font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>edges.<font color='#BB00BB'>size</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font> <font color='#5555FF'>=</font><font color='#5555FF'>=</font> <font color='#979000'>0</font><font face='Lucida Console'>)</font>
            <font color='#0000FF'>return</font> <font color='#979000'>0</font>;

        std::vector<font color='#5555FF'>&lt;</font>std::pair<font color='#5555FF'>&lt;</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font>, <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font><font color='#5555FF'>&gt;</font> <font color='#5555FF'>&gt;</font> neighbors;
        <font color='#BB00BB'>find_neighbor_ranges</font><font face='Lucida Console'>(</font>edges, neighbors<font face='Lucida Console'>)</font>;

        <font color='#009900'>// Initialize the labels, each node gets a different label.
</font>        labels.<font color='#BB00BB'>resize</font><font face='Lucida Console'>(</font>neighbors.<font color='#BB00BB'>size</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font><font face='Lucida Console'>)</font>;
        <font color='#0000FF'>for</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> i <font color='#5555FF'>=</font> <font color='#979000'>0</font>; i <font color='#5555FF'>&lt;</font> labels.<font color='#BB00BB'>size</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>; <font color='#5555FF'>+</font><font color='#5555FF'>+</font>i<font face='Lucida Console'>)</font>
            labels[i] <font color='#5555FF'>=</font> i;


        <font color='#0000FF'>for</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> iter <font color='#5555FF'>=</font> <font color='#979000'>0</font>; iter <font color='#5555FF'>&lt;</font> neighbors.<font color='#BB00BB'>size</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font><font color='#5555FF'>*</font>num_iterations; <font color='#5555FF'>+</font><font color='#5555FF'>+</font>iter<font face='Lucida Console'>)</font>
        <b>{</b>
            <font color='#009900'>// Pick a random node.
</font>            <font color='#0000FF'>const</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> idx <font color='#5555FF'>=</font> rnd.<font color='#BB00BB'>get_random_64bit_number</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font><font color='#5555FF'>%</font>neighbors.<font color='#BB00BB'>size</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>;

            <font color='#009900'>// Count how many times each label happens amongst our neighbors.
</font>            std::map<font color='#5555FF'>&lt;</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font>, <font color='#0000FF'><u>double</u></font><font color='#5555FF'>&gt;</font> labels_to_counts;
            <font color='#0000FF'>const</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> end <font color='#5555FF'>=</font> neighbors[idx].second;
            <font color='#0000FF'>for</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> i <font color='#5555FF'>=</font> neighbors[idx].first; i <font color='#5555FF'>!</font><font color='#5555FF'>=</font> end; <font color='#5555FF'>+</font><font color='#5555FF'>+</font>i<font face='Lucida Console'>)</font>
            <b>{</b>
                labels_to_counts[labels[edges[i].<font color='#BB00BB'>index2</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>]] <font color='#5555FF'>+</font><font color='#5555FF'>=</font> edges[i].<font color='#BB00BB'>distance</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>;
            <b>}</b>

            <font color='#009900'>// find the most common label
</font>            std::map<font color='#5555FF'>&lt;</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font>, <font color='#0000FF'><u>double</u></font><font color='#5555FF'>&gt;</font>::iterator i;
            <font color='#0000FF'><u>double</u></font> best_score <font color='#5555FF'>=</font> <font color='#5555FF'>-</font>std::numeric_limits<font color='#5555FF'>&lt;</font><font color='#0000FF'><u>double</u></font><font color='#5555FF'>&gt;</font>::<font color='#BB00BB'>infinity</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>;
            <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> best_label <font color='#5555FF'>=</font> labels[idx];
            <font color='#0000FF'>for</font> <font face='Lucida Console'>(</font>i <font color='#5555FF'>=</font> labels_to_counts.<font color='#BB00BB'>begin</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>; i <font color='#5555FF'>!</font><font color='#5555FF'>=</font> labels_to_counts.<font color='#BB00BB'>end</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>; <font color='#5555FF'>+</font><font color='#5555FF'>+</font>i<font face='Lucida Console'>)</font>
            <b>{</b>
                <font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>i<font color='#5555FF'>-</font><font color='#5555FF'>&gt;</font>second <font color='#5555FF'>&gt;</font> best_score<font face='Lucida Console'>)</font>
                <b>{</b>
                    best_score <font color='#5555FF'>=</font> i<font color='#5555FF'>-</font><font color='#5555FF'>&gt;</font>second;
                    best_label <font color='#5555FF'>=</font> i<font color='#5555FF'>-</font><font color='#5555FF'>&gt;</font>first;
                <b>}</b>
            <b>}</b>

            labels[idx] <font color='#5555FF'>=</font> best_label;
        <b>}</b>


        <font color='#009900'>// Remap the labels into a contiguous range.  First we find the
</font>        <font color='#009900'>// mapping.
</font>        std::map<font color='#5555FF'>&lt;</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font>,<font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font><font color='#5555FF'>&gt;</font> label_remap;
        <font color='#0000FF'>for</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> i <font color='#5555FF'>=</font> <font color='#979000'>0</font>; i <font color='#5555FF'>&lt;</font> labels.<font color='#BB00BB'>size</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>; <font color='#5555FF'>+</font><font color='#5555FF'>+</font>i<font face='Lucida Console'>)</font>
        <b>{</b>
            <font color='#0000FF'>const</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> next_id <font color='#5555FF'>=</font> label_remap.<font color='#BB00BB'>size</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>;
            <font color='#0000FF'>if</font> <font face='Lucida Console'>(</font>label_remap.<font color='#BB00BB'>count</font><font face='Lucida Console'>(</font>labels[i]<font face='Lucida Console'>)</font> <font color='#5555FF'>=</font><font color='#5555FF'>=</font> <font color='#979000'>0</font><font face='Lucida Console'>)</font>
                label_remap[labels[i]] <font color='#5555FF'>=</font> next_id;
        <b>}</b>
        <font color='#009900'>// now apply the mapping to all the labels.
</font>        <font color='#0000FF'>for</font> <font face='Lucida Console'>(</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> i <font color='#5555FF'>=</font> <font color='#979000'>0</font>; i <font color='#5555FF'>&lt;</font> labels.<font color='#BB00BB'>size</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>; <font color='#5555FF'>+</font><font color='#5555FF'>+</font>i<font face='Lucida Console'>)</font>
        <b>{</b>
            labels[i] <font color='#5555FF'>=</font> label_remap[labels[i]];
        <b>}</b>

        <font color='#0000FF'>return</font> label_remap.<font color='#BB00BB'>size</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>;
    <b>}</b>

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
    <font color='#0000FF'>inline</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> <b><a name='chinese_whispers'></a>chinese_whispers</b> <font face='Lucida Console'>(</font>
        <font color='#0000FF'>const</font> std::vector<font color='#5555FF'>&lt;</font>sample_pair<font color='#5555FF'>&gt;</font><font color='#5555FF'>&amp;</font> edges,
        std::vector<font color='#5555FF'>&lt;</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font><font color='#5555FF'>&gt;</font><font color='#5555FF'>&amp;</font> labels,
        <font color='#0000FF'>const</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> num_iterations,
        dlib::rand<font color='#5555FF'>&amp;</font> rnd
    <font face='Lucida Console'>)</font>
    <b>{</b>
        std::vector<font color='#5555FF'>&lt;</font>ordered_sample_pair<font color='#5555FF'>&gt;</font> oedges;
        <font color='#BB00BB'>convert_unordered_to_ordered</font><font face='Lucida Console'>(</font>edges, oedges<font face='Lucida Console'>)</font>;
        std::<font color='#BB00BB'>sort</font><font face='Lucida Console'>(</font>oedges.<font color='#BB00BB'>begin</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>, oedges.<font color='#BB00BB'>end</font><font face='Lucida Console'>(</font><font face='Lucida Console'>)</font>, <font color='#5555FF'>&amp;</font>order_by_index<font color='#5555FF'>&lt;</font>ordered_sample_pair<font color='#5555FF'>&gt;</font><font face='Lucida Console'>)</font>;

        <font color='#0000FF'>return</font> <font color='#BB00BB'>chinese_whispers</font><font face='Lucida Console'>(</font>oedges, labels, num_iterations, rnd<font face='Lucida Console'>)</font>;
    <b>}</b>

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
    <font color='#0000FF'>inline</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> <b><a name='chinese_whispers'></a>chinese_whispers</b> <font face='Lucida Console'>(</font>
        <font color='#0000FF'>const</font> std::vector<font color='#5555FF'>&lt;</font>sample_pair<font color='#5555FF'>&gt;</font><font color='#5555FF'>&amp;</font> edges,
        std::vector<font color='#5555FF'>&lt;</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font><font color='#5555FF'>&gt;</font><font color='#5555FF'>&amp;</font> labels,
        <font color='#0000FF'>const</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> num_iterations <font color='#5555FF'>=</font> <font color='#979000'>100</font>
    <font face='Lucida Console'>)</font>
    <b>{</b>
        dlib::rand rnd;
        <font color='#0000FF'>return</font> <font color='#BB00BB'>chinese_whispers</font><font face='Lucida Console'>(</font>edges, labels, num_iterations, rnd<font face='Lucida Console'>)</font>;
    <b>}</b>

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
    <font color='#0000FF'>inline</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> <b><a name='chinese_whispers'></a>chinese_whispers</b> <font face='Lucida Console'>(</font>
        <font color='#0000FF'>const</font> std::vector<font color='#5555FF'>&lt;</font>ordered_sample_pair<font color='#5555FF'>&gt;</font><font color='#5555FF'>&amp;</font> edges,
        std::vector<font color='#5555FF'>&lt;</font><font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font><font color='#5555FF'>&gt;</font><font color='#5555FF'>&amp;</font> labels,
        <font color='#0000FF'>const</font> <font color='#0000FF'><u>unsigned</u></font> <font color='#0000FF'><u>long</u></font> num_iterations <font color='#5555FF'>=</font> <font color='#979000'>100</font>
    <font face='Lucida Console'>)</font>
    <b>{</b>
        dlib::rand rnd;
        <font color='#0000FF'>return</font> <font color='#BB00BB'>chinese_whispers</font><font face='Lucida Console'>(</font>edges, labels, num_iterations, rnd<font face='Lucida Console'>)</font>;
    <b>}</b>

<font color='#009900'>// ----------------------------------------------------------------------------------------
</font>
<b>}</b>

<font color='#0000FF'>#endif</font> <font color='#009900'>// DLIB_CHINESE_WHISPErS_Hh_
</font>

</pre></body></html>